Re: [png-mng-implement] libpng bug tracker: possible rgb to gray inaccuracies

[<gl...@co...>]

The "inaccuracy" is within the variation between editions of
Poynton's document.  For instance, the red weight in his 1998-2002
version is .212671 (which we expressed as 6969/32768), while
from 2003 until now it is .2126 (i.e., 6966/32768).

Glenn